71042021 has 4 divisors (see below), whose sum is σ = 71197932. Its totient is φ = 70886112.

The previous prime is 71042017. The next prime is 71042039. The reversal of 71042021 is 12024017.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 12024017 = 19 ⋅632843.

It can be written as a sum of positive squares in 2 ways, for example, as 39513796 + 31528225 = 6286^2 + 5615^2 .

It is a cyclic number.

It is not a de Polignac number, because 71042021 - 2² = 71042017 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (71041021) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 77270 + ... + 78183.

It is an arithmetic number, because the mean of its divisors is an integer number (17799483).

Almost surely, 2^71042021 is an apocalyptic number.

It is an amenable number.

71042021 is a deficient number, since it is larger than the sum of its proper divisors (155911).

71042021 is a wasteful number, since it uses less digits than its factorization.

71042021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 155910.

The product of its (nonzero) digits is 112, while the sum is 17.

The square root of 71042021 is about 8428.6428919489. The cubic root of 71042021 is about 414.1634495839.

Adding to 71042021 its reverse (12024017), we get a palindrome (83066038).

The spelling of 71042021 in words is "seventy-one million, forty-two thousand, twenty-one".